This invention relates to the production of tricalcium silicate useful in the manufacture of Portland and other cements and in particular the manufacture of such materials in electric arc furnaces.
Portland cement is commonly prepared from certain indefinite compounds of lime, silica, alumina, iron oxide, magnesium oxide and smaller quantities of other oxides. The raw materials useful in the preparation of Portland cement include cement rock, limestone, marl, clay and shale, blast-furnace slag, and gypsum sand. One common method for preparing Portland cement comprises the crushing or grinding of the raw materials into a powder which is then processed in dry form or as a slurry. The mixture of raw materials is placed in a rotary kiln for calcinization and burning into clinker. Temperatures of about 2800.degree. F. are typically used at the hottest heating zone near the discharge end of the kiln. Following heating, the clinker is air-cooled, pulverized and blended with various chemicals added to modify performance or setting time and then bagged or otherwise stored for use. This method is not wholly satisfactory because it requires a large amount of energy and controlling the composition of the final product is relatively difficult.